1. Field of the Invention
The present invention relates to an electronic ignition circuit for the self-destruction of a projectile fuse with a voltage source and a charging condenser which determines the time interval until self-destruction whereby, after the reaching of a predetermined minimum voltage at the voltage potential pole of the charging condenser, there responds a threshold switch such as, for instance, a four-layer diode or a transistor circuit, and an igniter is ignited, and wherein an electronic control circuit is connected between the voltage potential pole of the voltage source and the voltage potential pole of the charging condenser.
2. Discussion of the Prior Art
Presently known from German Published Patent Specification No. 1,155,037, German Laid-open Patent Specification No. 2,113,126 and German Published Patent Specification No. 2,104,422 are circuits in which an ohmic resistor is located between the voltage potential pole of a voltage source constructed from a storage condenser or capacitor and the voltage potential pole of the charging condenser. This resistor, in conjunction with the charging condenser, determines the current and voltage cycle of the recharging sequence.
In the presently known circuits, towards the end of the recharging sequence preceding the actuation of the threshold switch, in effect, at only a still smaller potential difference between the voltage potential poles of the storage condenser and a charging condenser, there flows a correspondingly lesser current. This current must, however, be greater than the current flow which is necessary for the switching of the threshold switch, which is nevertheless low; however, must be available in each instance. For this purpose, the threshold value of the threshold switch must be reached at a voltage level at which a current flows which is still adequate for the switching: The dimensioning of the circuit pursuant to German Published Patent Specification No. 1,155,037 and the German Laid-open Patent Specification No. 2,113,126, and the selection of the components therein, are hereby set by narrowly confined limits.
In German Published Patent Specification No. 2,104,422, for the dependable initiation of the ignition of the igniter, even at low voltages and large time constants for the recharging sequence, there is proposed a feedback circuit. In this circuit a field effect transistor is located between the voltage potential poles of the storage condenser and the charging condenser, whose drain source section is coupled in feedback, by means of a repeating coil, to the gate electrode. However, the utilization of repeating coils is mostly undesirable, since these are relatively large and complex components.